This specification relates to message queues.
User devices, e.g., mobile devices, can receive messages, e.g., text messages, e-mail messages, or other messages from other user devices or computer systems over a network, e.g., the Internet. The received messages can be stored by a server system and can be provided to a user device when the user device provides a request to receive messages. The server system can then provide stored messages for receipt by the user device.